Mole plough depth control mechanism

ABSTRACT

A mole plough having a plough blade rigidly secured to a support pivotally connected to a tracked carriage about a transverse horizontal axis, the blade having a rigid forward portion and a trailing foot portion pivotally connected thereto and means for tilting the foot portion relative to the remainder of the blade whereby the alteration of the angle of the undersurface of the foot portion and the reaction of the foot portion against the ground below the blade effects a change in the operating depth of the blade.

United States Patent Ede [451 June 20, 1972 [541 MOLE PLOUGH DEPTHCONTROL [561 References i d MECHANISM UNITED STATES PATENTS [72]Inventor: Ainsley Neville Ede, Cambridge, England 25,902 10/1859 Jones..37/ 193 [73] Assignee: Hudswell Yates Developments Limited, LeedsYmkshlre, 26,355 12/1859 Hinckley. [22] Filed: Sept. 25, 1970 2,715,2868/1955 Saveson ..37/193 [21] APPL 75 720 Primary Examiner-Robert E.Pulfrey Assistant ExaminerCliff0rd D. Crowder Related U.S. ApplicationData Attarneylmirie & Smiley [63] Continrfitiojn-in-part of Ser. No.715,469, March 8, [57] ABSTRACT 1968 a an oned' A mole plough having aplough blade rigidly secured to a support pivotally connected to atracked carriage about a trans- [30] Foreign Apphcanon Pnonty Data versehorizontal axis, the blade having a rigid forward portion March 10, 1967Great Britain ..11,287/67 and a trailing foot portion pivotallyconnected thereto and means for tilting the foot portion relative to theremainder of [52] U.S. Cl ..37/l93, 172/699, 172/736 the blade wherebythe alteration of the angle of the undersur- [5 1] face of the footportion and the reaction of the foot portion [58] against the groundbelow the blade effects a change in the operating depth of the blade.

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SHEET 20F 2 MOLE PLOUGI'I DEPTH CONTROL MECHANISM This application is acontinuation in -part of application Ser. No. 715,469 filed March 8,1968, now abandoned.

The invention relates to apparatus for use in pipelaying and similaroperations, and particularly to mole plough apparatus incorporating amember-which is supported at least partially below ground in use, themember being hauled along as by a tractor or winch whereby it produces abelow-ground passage or tunnel.

The invention is particularly concerned with means for adjusting thedepth below ground of the passage or tunnel.

According to the invention, there is provided mole plough apparatus,comprising a support, a mole plough element rigidly attached to saidsupport, means for applying a force to said support whereby to drag saidmole plough element through the ground to produce a passage through theground at a desired working depth, said mole plough element having aforward portion rigid with said support and a trailing foot memberhinged to said forward portion about a horizontal axis transverse to thedirection of movement of the mole plough element in use, the lowersurface of said trailing foot member constituting part of the undersurface of the mole plough element, and power means coupled to said footmember and operable to tilt same relative to the remainder of the moleplough element, whereby to alter the angle of the under surface of themole plough element relative to the horizontal and thereby, throughground reaction, to tend to alter the working depth of the mole ploughelement.

Mole plough apparatus embodying the invention will now be described byway of example only with reference to the accompanying drawings inwhich:

FIG. 1 is a diagrammatic side elevation of one form of apparatus;

FIG. 2 is a cross-section on the line 2-2 of FIG. 1;

FIG. 3 is a diagrammatic side elevation of a further form of apparatus;

FIG. 4 is a cross-section on'the line 44 of FIG. 3; and

FIG. 5 is a diagrammatic side elevation showing a modification of theapparatus of FIGS. 1 and 2.

In all the Figures, the ground level is indicated by the line A.

Referring to FIGS. 1 and 2, a mole plough blade is rigidly attached to abeam 1 1 and has a forward portion rigid with the beam and a trailingfoot which is wedge-shaped and is pivoted about a transverse horizontalaxis 21 near the point of the blade, the rear of the foot being movableup and down through a range of a few inches by means of a stiff rod 22actuated by a vertically placed hydraulic ram 23 above ground level. Asshown in FIG. 2, the cross section of the foot of the blade is more orless rectangular, which is required to give the necessary soil surfacearea and to exclude dirt from entering between the foot and the blade.An expander 10b, to increase the cross-section of the bottom of thepassage cut through the soil, is carried at the rear of the foot of theblade 10 and is substantially circular in crosssection and of diametergreater than the width of the foot.

In use, the end of the beam 11 opposite to the blade 10 is pivotallysupported on a tracked carriage (not shown) which is hauled along theground so that the blade 10 cuts a slit trench through the ground. Whenthe angle of incidence of the foot 20 is altered by tilting about axis21, the effect is for the blade to move along the new line made by thefoot. Thus, if the blade is below the required depth, the rear of thefoot is moved downwards causing the blade to rise, or vice versa. Thetilting foot portion may be of enlarged width relative to the remainderof the blade. It should be noted that the upper surface of the blade isnot materially important in regulating grade or depth as, although theforces on it are heavy, the changes in force accompanying changes inangle are light in comparison with the lower surfaces which are workingagainst undisturbed soil. Moreover in each working position the bladeseeks a position in which its lower surface is generally parallel withthe line of pull and the blade continues to operate at this depth untilfurther adjustment of the foot 20 is effected.

The apparatus of FIGS. 3 and 4 has a cylindrical mole plough element 24rigidly attached to the foot of the blade 10. An actuating ram 25 isplaced horizontally within the nose of the mole 24, and controls thehorizontal shifting of a pad or roller 26 at the rear of the mole. Thepad or roller 26 controls the separation between the inclined uppersurface 27 of a mole foot 28 and another surface 29 formed inside theroof of the rear of the mole, the foot 28 being pivoted to the rest ofthe mole about a transverse horizontal axis 28a. As in the case of theV-blade 10 of FIGS. 1 and 2, a more or less rectangular cross section isrequired for the base. The ram 25 is controlled through hydraulic pipelines 25a and and controls the depth of the element by adjusting theangle of the foot 28 as in the arrangement of FIGS. 1 and 2.

The utilization of these systems of grade control enable the desirablysluggish reactions of the blade or mole to variations in elevation ofthe carriage to be combined with sufficiently quick reaction to depthcontrol signals as received from an automatic system. It will be notedthat depth changes are effected by alterations in ground reactionbrought about by application of a vertical force to the trailing end ofthe pivoted foot portion. This indirect technique enables sufficientforce to be applied to overcome the high resistance present, the latterbeing such that a direct pivotal movement of the leading edge of theblade or bodily lifting of the blade are impractical.

FIG. 5 illustrates a modification applicable to any of the arrangementsillustrated in the other Figures though it is shown as appliedparticularly to the arrangements of FIGS. 1 and 2. A hydraulic ram 30 isprovided for raising the beam 11 and blade 10 clear of the ground fortransport purposes, and is arranged in addition to apply constantregulatable vertical pressure to the beam assembly when the plough is inuse, though there is no vertical constraint on the beam. This enablesadditional downward force to be applied to the blade 10 when the bladeis operating at extreme depth and the vertical component of force of theblade is barely sufficient to hold it down. The reverse is the case whenoperating in very soft soils such as peat, when the force due to theweight of the beam and blade predominates, and a controlled upward forcecan be ap plied by the ram 30 in order to leave a distinct but smallresidual force to be borne by the foot of the blade 10 for gradingpurposes in the manner described in connection with the other Figures.The ram 30 is actuated hydraulically from a feed and pressure controlsystem 31 leading to a selector valve 32 having connections 33, 34 withopposite ends of the ram cylinder 35.

As explained above, the tracked carriage, to which the beams 11 of thearrangements illustrated are pivotally attached, is winch-hauled anddoes not rely upon its tracks for gripping the ground; a further featurewhen additional bearing surface is required in soft ground is theprovision of a plate lowered under driver control by four hydraulicrams. The plate, with turned-up ends to assist in riding over the soil,lowers to a position occupying the space between, and level with, thelower surface of the tracks; alternatively the plate could occupy afixed position.

Various other modifications may be made without departing from theinvention. For example, the trailing foot portion could be pivoted atany suitable point along the lower edge of the blade and couldconstitute the forward portion of the lower edge of the blade, therearward portion being rigid with the blade. In all cases the foot formsat least a part of the lower edge of the blade and the leading edge ofthe blade is rigid with the blade proper and is not subjected to anyangular or bodily movement except such as is derived from angularmovement of the foot. Moreover, while in the drawings the lower edges ofthe blade and of the foot are coplanar in their mean positions, theycould alternatively be inclined to one another, that is the lower edgeof the foot portion could be inclined upwardly or downwardly relative tothe lower edge of the blade proper.

I claim:

1. Mole plough apparatus, comprising a support, a mole plough elementrigidly attached to said support, means for applying a force to saidsupport whereby to drag said mole plough element through the ground toproduce a passage through the ground at a desired working depth, saidmole plough element having forward and upper portions rigid with saidsupport and a trailing foot member hinged behind said forward portionand below said upper portion about a horizontal axis transverse to thedirection of movement of the mole plough element in use, said trailingfoot member having a lower surface constituting part of the undersurface of the mole plough element, and power means coupled to said footmember and operable to tilt same relative to the remainder of the moleplough element, whereby to alter the angle of the under surface of themole plough element relative to the horizontal and thereby, throughground reaction, to tend to alter the working depth of the mole ploughelement.

2. Apparatus according to claim 1 including an expander member attachedto the rear edge of said foot member, the expander member having asubstantially circular cross-section with its diameter parallel to, andgreater in length than, the width of said foot member.

3. Apparatus according to claim 1, wherein said mole plough elementcomprises a blade, said power means comprising a piston-cylinderassembly including a piston rod enclosed within said blade and connectedto said foot member for swinging the foot member about said transversehorizontal axis.

4. Apparatus according to claim 1, wherein said foot member is enlargedin width relative to the remainder of said mole plough element.

5. Apparatus according to claim 1, wherein said support comprises anelongated beam pivotally connected to a forward portion of theapparatus, and including force-applying means connected to the beam andoperative to apply a vertical force thereto.

6. Apparatus according to claim 1, wherein said mole plough elementincludes an upper blade member and a lower substantially cylindricallyshaped mole assembly, said mole assembly comprising an upper portionrigid with the lower end of said blade member, said foot member beinghinged to said upper portion about said transverse horizontal axis, andsaid upper portion overlapping said foot member.

7. Apparatus according to claim 6, wherein said power means includesactuating means disposed within said upper portion and operative topivot said lower portion about said axis, said actuating meanscomprising a ram engaging and movable between facing mutually inclinedsurfaces respectively attached to said upper and lower portions.

1. Mole plough apparatus, comprising a support, a mole plough elementrigidly attached to said support, means for applying a force to saidsupport whereby to drag said mole plough element through the ground toproduce a passage through the ground at a desired working depth, saidmole plough element having forward and upper portions rigid with saidsupport and a trailing foot member hinged behind said forward portionand below said upper portion about a horizontal axis transverse to thedirection of movement of the mole plough element in use, said trailingfoot member having a lower surface constituting part of the undersurface of the mole plough element, and power means coupled to said footmember and operable to tilt same relative to the remainder of the moleplough element, whereby to alter the angle of the under surface of themole plough element relative to the horizontal and thereby, throughground reaction, to tend to alter the working depth of the mole ploughelement.
 2. Apparatus according to claim 1 including an expander memberattached to the rear edge of said foot member, the expander memberhaving a substantially circular cross-section with its diameter parallelto, and greater in length than, the width of said foot member. 3.Apparatus according to claim 1, wherein said mole plough elementcomprises a blade, said power means comprising a piston-cylinderassembly including a piston rod enclosed within said blade and connectedto said foot member for swinging the foot member about said transversehorizontal axis.
 4. Apparatus according to claim 1, wherein said footmember is enlarged in width relative to the remainder of said moleplough element.
 5. Apparatus according to claim 1, wherein said supportcomprises an elongated beam pivotally connected to a forward portion ofthe apparatus, and including force-applying means connected to the beamand operative to apply a vertical force thereto.
 6. Apparatus accordingto claim 1, wherein said mole plough element includes an upper blademember and a lower substantially cylindrically shaped mole assembly,said mole assembly comprising an upper portion rigid with the lower endof said blade member, said foot member being hinged to said upperportion about said transverse horizontal axis, and said upper portionoverlapping said foot member.
 7. Apparatus according to claim 6, whereinsaid power means includes actuating means disposed within said upperportion and operative to piVot said lower portion about said axis, saidactuating means comprising a ram engaging and movable between facingmutually inclined surfaces respectively attached to said upper and lowerportions.